Slinky – Richard James
In 1943, Navy engineer Richard James was trying to figure out how to use springs to keep the sensitive instruments aboard ships from rocking themselves to death, when he knocked one of his prototypes over. Instead of crashing to the floor, it gracefully sprang downward, and then righted itself. So pointless — so nimble — so slinky. The spring became a goofy toy of many childhoods—that is before every kid inevitably gets theirs all twisted up and ruins it. 300 million sold worldwide!